A rapid, sensitive, reversed-phase high-performance liquid chromatographic procedure was developed for the quantitative analysis of indoprofen in plasma and urine. Minimal sample preparation is required for the analysis of unconjugated urinary or plasma drug levels. The method provided quantitative results for indoprofen levels of 0.5-50 microgram/ml of plasma and 0.5-200 microgram/ml of urine and had a lower detection limit of 1 ng. Total urinary indoprofen levels required enzymatic hydrolysis of the conjugated drug prior to analysis. Results are presented for the plasma and urinary excretion levels of indoprofen for a patient receiving a single oral dose.